flyinfool1

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I was looking at getting the X-132 to put in a SAB Lizard. Everything I read about it says it the best possible choice. Smaller, lighter, faster spool up, lower fuel burn, lower price, reputable brand.

I was just about ready to pull the trigger to order one, and was reading the Users Manual and got scared.

On page 39 of the manual it states...

Has anyone had any experience with Xicoy X-132 doing fast 3D?

What would be the next best choice for a 3D jet that can handle the fast maneuvers?

acw

My Feedback: (1)

Great question. I have used a Xicoy 180 and 195 in a 3d plane for a few hours without any issue so far and I'm about to use a 240 in my Ares L to replace the original engine (not Xicoy) that only survived the 3D abuse for 2h of run time.
Apparently, most 3d pilots in Europe are using Jetcat for that reason... Would go straight to Jetcat but they are hard to get in the US.

It would be good for Xicoy to publish actual limitations. Jetcat started to do that with their "pro" engines.

flyinfool1

My Feedback: (2)

This brings up my next question. You said you had an engine only survived for 2 hours of 3D. What was the failure mode? DO the planes that have the Xicoy loop or spin faster than 1 second?

Since most turbines use the same or similar bearings is this an issue for all turbines?
Is Xicoy tho only one honest enough to list a limitation?
In the quote from the manual they do say that the limitation is 360° / second, by saying a loop in under 1 second. A loop or a spin is the same forces, the turbine does not know its orientation.

I was hoping that someone from Xicoy would chime in for some real discussion. I still would like the Xicoy, but need more info. If my angular deviation is kept to less than 360° per second is it safe for the turbine?
I can adjust the throw on the TV to keep the loop/spin rate to slower than 1 second. Is a 1+ second spin or loop rate still fast enough to do 3D with a jet?

acw

My Feedback: (1)

Hello Jeff,

Great conversation. Hopefully someone with more experience will chime in. The thread below talks about the failure I experienced and is very related:
https://www.rcuniverse.com/forum/rc-...an-handle.html

I had a 180 in my Eurosport is vector thrust for a few hours. Maybe 5 hours or so. I'm new to 3d in jets and wasn't super familiar with this issue so I did plenty of flat spins, positive and negative tumbles with it. I just replaced it with a Xicoy 195 to get more power during hover. I think the jury is still out on this one given the very low hours.

I don't read the Xicoy manual mention of 3d flight as a hard limitation but rather as a data point. They only say that gyroscopic forces induced by rotation less than 1 second can destroy the engine. Doesn't address where the limit actually is. For example, is a full rotation say on pitch acceptable if between 1 and 2 seconds. (as you mentioned).

My own conclusion so far is to avoid full power fast rotations on pitch and yaw. So for example, if I'm going to exit a vertical line hover with a tumble, I will induce the tumble with lots of pitch but not full throttle to reduce RPM and do everything I can to reduce the speed of rotation. I don't think reducing the throw is workable because you occasionally need all of it to prevent the plane from exiting some desired path.

I might be wrong but I don't think we know for a fact that all these engines are using the same bearings and other components. I understand the torsional rigidity of the case matters as well. Also the clearance between compressor wheel and case / turbine wheel and case matter as well.

It would be good for experienced 3d jet pilots to share what works for them. Yeah 3d is hard on engines but what's the best way to mitigate.

Arnaud

flyinfool1

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SO maybe set up a dual rate on the TV where on low rate it would give a max spin/flip rate of say 200° / second and hi rate could still be used for high alpha type maneuvers?

Do any of the gyros have an option to program in a max rotational rate so you could still have full throw available for some maneuvers that need it like high alpha flight, but yet not exceed the limits of the turbine in pitch or yaw rates when flipping and spinning?

FenderBean

Lets talk Turbine 101 here, lets start with some facts that apply to any turbine in the RC market.

1st, High G aerobatics have been and will always be bad for your "turbine" motor, it 100% will shorten the life span of the bearings and if they fail will damage the motor.

2nd, Hovering any motor prevents normal airflow through the model, over the motor/through and out the rear. This 100% will over heat the rear bearing which again decreases the life span of the bearing and if it fails will damage the motor.

Xicoy specific, the motors have high tolerances as do most turbines and something like the X45 which is tiny and turning 225K RPMs have less room for play in bearings as well as do most turbines regardless of the size.

other than being less aggressive there is no way to mitigate the affects on the turbine all you will do is change time the bearing will fail or wear out.

acw

My Feedback: (1)

Hey Keith, about your 2nd point, I don't understand why hovering is worse than running the engine on the ground or on a bench. Or are both equally bad due to lack of airflow?

FenderBean

Well for one you dont run the motor on a test stand for 25 hours and two most hovering is in the high end of the thrust/rpm which equals high temp which normally equates to speed and more wind velocities that you are not getting while hovering.
Turbine design in general is not developed around what you are doing so again you can do what ever you like but like I stated it will shorten life span on ANY turbine out there.

flyinfool1

My Feedback: (2)

I asked this question to be educational for me and others. Xicoy is the only manual that I have seen a 3D warning ( I admit I have only read a few). As I asked near the top, Is it just that Xicoy is the only maker honest enough to state their limitations?
I will be buying a turbine and doing 3D with it. At this point I am still pondering ways to reduce the added wear that 3D will impose on the Turbine.

Xicoy kind of implies that spin or flip rates faster 360° per second are bad, does that mean that Xicoy can handle spin/flip rates slower than 1/sec?

I understand that 3D is bad for all turbines. The question is, is it worse for some than others?
It is my understanding that Xicoy gets its better than most others performance by having tighter clearances than anyone else. Tighter clearances means less room for things to deflect before unwanted contact occurs.

Ideal would be if all makers listed max allowable rotation rates so that fliers would know what the limitations are. I think that it would not be difficult for the makers of modern high end gyros to include a feature to limit rotation rates and/or G force, the hardware is already in the gyros. But to make use of it the turbine manufacturers would have to do like Xicoy and state a limit for their design.

This is my first 3D capable jet with thrust vectoring. I have no idea at this moment in time just how fast of a rotation rate is possible or even desirable or how much throttle will be necessary to achieve desired results. Or for that matter what it is that I would even consider as desirable.